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AMD Trinity Linux Memory Performance

10-05-2012, 08:10 AM

Phoronix: AMD Trinity Linux Memory Performance

Following the initial AMD A10-5800K Trinity on Linux article earlier in the week, many forum goers were discussing the impact that the system memory speed has on the overall performance for this latest generation APU. In this benchmark are results looking at the impact of the Linux performance as the DDR3 memory operates at speeds from 800MHz through 2133MHz.

I may have missed it, but what were the memory timings for speeds other than 2133?

2133: 11-11-11-27

From those latency values, the following are the closest without going over:
1866:10-10-10-24
1600:9-9-9-21
1333:7-7-7-17(round up to a multiple of 3, I think) so 18
1066:6-6-6-6-14(round to 15)
800:5-5-5-11(round to 12)

Close settings that only exceed the original timings by a tiny bit:
1600:8-8-8-21
800:4-4-4-12

If you left the clocks at 10-10-10-24 for all clock speeds, you're testing not just memory bandwidth, but latency tolerance as well.

It seems to be a rather linear dependency that the chip has on the memory. Looks to me like AMD may have a very solid platform, but needs to focus more on memory bandwidth. These AMD chips are still dual channel aren't they? And Intel runs triple channel on some of their chips? With AMD, you need to step all the way up to an Opteron 6000 to break over 2 memory channels (Opteron 6000 are 4-channel rectangular chips, lots of pins!).

It seems to be a rather linear dependency that the chip has on the memory. Looks to me like AMD may have a very solid platform, but needs to focus more on memory bandwidth. These AMD chips are still dual channel aren't they? And Intel runs triple channel on some of their chips? With AMD, you need to step all the way up to an Opteron 6000 to break over 2 memory channels (Opteron 6000 are 4-channel rectangular chips, lots of pins!).

How about it AMD? 8-channel desktop chips?

For quite some time almost all AMD and Intel desktop chips have had dual channel memory. There was the i9x0 family that had triple channel and there is the uber-expensive SB-E with four, but most chips you're going to see have two channels. The Atom, the 'C', and 'E' series chips are all single channel.

The Opteron chips with more than two memory channels are dual-die (two chips in one package), so it's not much different than a dual socket MB with two channels/processor. It's just all in one nice (huge) package, so it makes 8P system easier to build for the hardware vendors.

We're not likely to see an 8 channel chip in the near future--at least until memory starts to get integrated onto the processor package itself. That's going to be a strange day. Of course, some of the upcoming Intel Haswell variants are expected to have *some* memory on the package in a separate die--much like the old Pentium-Pro and PII/PIII era Slot-1 processors did. Oh, and the Slot-A from AMD was that way in the beginning, too.

That said, AMD can certainly improve its memory controllers. In similar processors, Intel has had a lead in bandwidth and latency in its memory controllers at least since the Core2 family came out. DDR4 is coming in a year or so, so that will bring higher memory clock speeds and some improvements in bus efficiency.

Comment

Nice review Michael, thanks. 8GB 1600MHz kit cost something about 30? in Europe, the same as 1333 and 1060. So obviously it's slowest ram that one should buy for these apus. Faster rams cost some 10? more, so if one wants cheap performance boost, buy faster rams.

That 1866 MHz rams gives some odd results, lost couple of times even 1333MHz rams how so?

Are you doing cpu test next? It could be interesting to see how this apu's 4-core piledriver fares vs equally clocked 4-core bulldozer FX-4100 series.

Comment

For quite some time almost all AMD and Intel desktop chips have had dual channel memory. There was the i9x0 family that had triple channel and there is the uber-expensive SB-E with four, but most chips you're going to see have two channels. The Atom, the 'C', and 'E' series chips are all single channel.

The Opteron chips with more than two memory channels are dual-die (two chips in one package), so it's not much different than a dual socket MB with two channels/processor. It's just all in one nice (huge) package, so it makes 8P system easier to build for the hardware vendors.

We're not likely to see an 8 channel chip in the near future--at least until memory starts to get integrated onto the processor package itself. That's going to be a strange day. Of course, some of the upcoming Intel Haswell variants are expected to have *some* memory on the package in a separate die--much like the old Pentium-Pro and PII/PIII era Slot-1 processors did. Oh, and the Slot-A from AMD was that way in the beginning, too.

That said, AMD can certainly improve its memory controllers. In similar processors, Intel has had a lead in bandwidth and latency in its memory controllers at least since the Core2 family came out. DDR4 is coming in a year or so, so that will bring higher memory clock speeds and some improvements in bus efficiency.

Eh, one die, two die, red die, blue die.

What we need is more memory bandwidth. Period. The northbridge can handle it.

Comment

Michael (or anyone else), is there any visible reason why DDR3 1866 MHz RAM was sometimes on lower performance than the 1600 equivalent? On most tests it showed a relatively "linear" behaviour, but on others it left the queue with a jump.
I guess all of them were default and configured by SPD on chip/bar?